The present invention relates to a vertebral prosthesis comprised of essentially two generally cylindrical members, which are connected by means of a screw mechanism in such a manner that the overall axial length of the connected members can be varied.
U.S Pat. No. 4,554,914 describes a vertebral prosthesis of this type which consists of a first male screw-like element and a second female tubular element with an internal screw thread. After screwing one element into the other, the assembly constitutes a pin-like support, whose free ends taper to points for penetrating the adjacent vertebrae. As a vertebral prosthesis two such pins are arranged adjacent to each other to function as distance pieces between two healthy vertebrae. In order to prevent shearing forces in the known design the adjacent vertebrae are additionally anchored with plates.
One object of the present invention is to provide a vertebral prosthesis of the aforementioned type the implantation of which does not require additional anchoring means and is easily performed.